320 
BRITISH ENTOMOSTRACA. 
of their existence they fasten themselves upon their prey 
is at present unknown ; but no sooner apparently does 
this happen than the eye disappears, and the feet either 
disappear also, or are transformed into other organs. In 
some they are changed into foot-jaws, by means of which 
they fix themselves upon the body of the fish they select 
for their habitation. In others they are transformed into 
long and strong prolongations like arms, which unite 
together either at the tips only, or from the roots all the 
way up to the point, where they send forth a short horny 
stem, that widens into the shape of a round button, and 
which, when buried in the skin or flesh of the fish, forms 
such a strong attachment, that the Lerneadse cannot be 
detached without being torn, or by being carefully dis- 
sected out. Most probably the species in which this 
development takes place first fasten themselves to their 
foster-mother by the foot~jaw r s, as the first-mentioned set 
do, and after being buried in the flesh, these organs 
assume this peculiar formation, otherwise it is difficult to 
conceive how such an instrument could penetrate deeply 
into the body of the fish. A third mode of transforma- 
tion of the feet appears to be into a series of horny 
branchlets developed round the mouth, and which, when 
they have penetrated deeply into the soft parts of their 
host, serve effectually to retain the parasite in its place. 
The adult Lerneadse show, with the exception of taking 
food and laying eggs, very few and feeble signs of life, 
whether attached to the nourishing animal or when sepa- 
rated from it. Many of the genera show no external 
signs of life at all after separation from their foster-mother; 
others move their jaws for a short period, or their head 
may be seen to move leisurely in different directions for a 
little time and then cease. In one species (L. branchialis ), 
Kroyer tells us, that he observed a singular phenomenon 
that nobody else had before noticed. When he touched 
an individual, it squirted, he says, “ from the vent, a 
transparent stream of fluid to the distance of a foot and 
a half, and this it repeated several times one after 
another.” 
